To those LUCKY few who have actually driven a Slingshot - Anybody compared the speedometer to a GPS? Any idea how accurate the speedometer is? I assume the unit is from a Victory or Indian. If so, anyone know how accurate the Victory or Indian speedometer is? Both of my Suzuki motorcycles seem to have speedometers that read about 10% over, meaning I need to do an indicated 66 mph to achieve 60 mph. At the same time, both of my Suzuki motorcycles seem to have accurate odometers to track mileage. Just wondering.